Method and system for integrated pitch control mechanism actuator hydraulic fluid transfer

ABSTRACT

The variable pitch propeller assembly includes a hub. The variable pitch propeller assembly also includes a plurality of propeller blade assemblies spaced circumferentially about the hub. Each of the plurality of propeller blade assemblies configured to rotate a respective propeller blade. The variable pitch propeller assembly also includes a hydraulic fluid port assembly integrally formed and including at least three hydraulic fluid ports configured to receive respective flows of hydraulic fluid from a stationary hydraulic fluid transfer sleeve. The variable pitch propeller assembly also includes a pitch actuator assembly coupled in flow communication with at least three hydraulic fluid ports through respective hydraulic fluid transfer tubes. The pitch actuator coupled to the plurality of propeller blade assemblies to selectively control a pitch of the propeller blades. The pitch actuator assembly includes a travel stop configured to limit a rotation of at least one of the pitch actuator assemblies.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 16/532,905 filed Aug. 6, 2019, which is a continuation applicationof U.S. application Ser. No. 15/043,036 filed Feb. 12, 2016, which is anon-provisional application, and wherein the above applications arehereby incorporated by reference in its entirety.

BACKGROUND

The field of the disclosure relates generally to gas turbine enginesand, more particularly, to a method and system for supplying hydraulicfluid to an integrated pitch control mechanism (PCM) actuator.

Gas turbine engines typically include a fan assembly that provides airto a core engine and compresses the air to generate thrust. At leastsome known fan assemblies include variable pitch fan blades that arecontrolled by externally modulated flows of hydraulic fluid. Fan bladepitch controls the performance of the fan, so it may be optimized atvarious aircraft conditions. Fan pitch is typically controlled byhydraulic fluid transfer from a stationary supply system to a rotatingactuator. At least some known gas turbine engines use an intermediatetubing mechanism to supply hydraulic fluid to the rotating actuator fromthe stationary supply system. Intermediate tubing mechanisms add weightto the aircraft and occupy valuable space on the engine.

BRIEF DESCRIPTION

In one aspect, a variable pitch propeller assembly is provided. Thevariable pitch propeller assembly includes a hub rotatable about a shafthaving an axis of rotation. The variable pitch propeller assembly alsoincludes a plurality of propeller blade assemblies spacedcircumferentially about the hub. Each of the plurality of propellerblade assemblies configured to rotate a respective propeller blade abouta radially extending pitch axis of rotation. The variable pitchpropeller assembly also includes a hydraulic fluid port assemblyintegrally formed and rotatable with the shaft. The hydraulic fluid portassembly includes at least three hydraulic fluid ports configured toreceive respective flows of hydraulic fluid from a stationary hydraulicfluid transfer sleeve at least partially surrounding the port assembly.The variable pitch propeller assembly also includes a pitch actuatorassembly coupled in flow communication with at least three hydraulicfluid ports through respective hydraulic fluid transfer tubes extendingaxially from the hydraulic fluid port assembly to the pitch actuator.The pitch actuator coupled to the plurality of propeller bladeassemblies to selectively control a pitch of the propeller blades. Thepitch actuator assembly includes a travel stop configured to limit arotation of at least one of the pitch actuator assemblies and theplurality of propeller blade assemblies.

In another aspect, a method of operating a variable pitch fanselectively controlled using an integrated pitch control mechanism (PCM)actuator assembly is provided. The PCM assembly includes a stationary torotary fluid transfer assembly and a PCM actuator formed as an integraldevice. The method includes channeling a plurality of flows of hydraulicfluid between a source of modulated hydraulic fluid and a stationarytransfer member of the stationary to rotary fluid transfer assembly. Themethod also includes directing the plurality of flows of hydraulic fluidacross a gap between the stationary transfer member and a rotatabletransfer member of the stationary to rotary fluid transfer assembly. Themethod also includes channeling the plurality of flows of hydraulicfluid to an actuation cavity of the PCM actuator. The method alsoincludes selectively moving an actuation member of the PCM actuatorbased on relative pressures of the plurality of flows of hydraulicfluid.

In yet another aspect, a variable pitch turbofan gas turbine engine isprovided. The variable pitch turbofan gas turbine engine includes a coreengine including a multistage compressor and a fan assembly comprisingan axis of rotation and powered by the core engine. The fan assemblyincludes a hub rotatable about a shaft having an axis of rotation. Thefan assembly also includes a plurality of propeller blade assembliesspaced circumferentially about the hub. Each of the plurality ofpropeller blade assemblies configured to rotate a respective propellerblade about a radially extending pitch axis of rotation. The fanassembly also includes a hydraulic fluid port assembly integrally formedand rotatable with the shaft. The hydraulic fluid port assembly includesat least three hydraulic fluid ports configured to receive respectiveflows of hydraulic fluid from a stationary hydraulic fluid transfersleeve at least partially surrounding the port assembly. The fanassembly also includes a pitch actuator assembly coupled in flowcommunication with the at least three hydraulic fluid ports throughrespective hydraulic fluid transfer tubes extending axially from thehydraulic fluid port assembly to the pitch actuator. The pitch actuatorcoupled to the plurality of propeller blade assemblies to selectivelycontrol a pitch of the propeller blades. The pitch actuator assemblyincludes a travel stop configured to limit a rotation of at least one ofthe pitch actuator assemblies and the plurality of propeller bladeassemblies.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIGS. 1-12 show example embodiments of the method and apparatusdescribed herein.

FIG. 1 is a schematic view of an exemplary gas turbine engine.

FIG. 2 is a side elevation view of a gas turbine engine fan rotorassembly including a PCM actuator assembly.

FIG. 3 is an exploded view of an integrated PCM actuator assembly.

FIG. 4a is a perspective view of a pitch actuator. FIG. 4b is a cutawayperspective view of a pitch actuator.

FIG. 5a is a perspective view of an actuator shell, a hydraulic fluidtransfer sleeve, and an end cap. FIG. 5b is a cutaway perspective viewof an actuator shell, a hydraulic fluid transfer sleeve, and an end cap.

FIG. 6 is an axial view of the integrated PCM actuator assemblies shownin FIGS. 3, 4, 5, and 7 along lines 6-6 in FIGS. 4, 5, and 7. FIG. 6a isan axial view of the integrated PCM actuator assembly in a normaloperational embodiment. FIG. 6b is an axial view of the integrated PCMactuator assembly in a decreased pitch operational embodiment.

FIG. 7 is a side elevation view of an integrated PCM actuator assembly.

FIG. 8 is an overlay of the internal flow passages of an actuator shellon a pitch actuator.

FIG. 9 is an axial view of the integrated PCM actuator assembly shown inFIGS. 3, 4, 5, and 7 along lines 9-9 in FIGS. 4, 5, and 7. FIG. 9adepicts a normal operational embodiment of integrated PCM actuator. FIG.9b depicts a decreased pitch operational embodiment of integrated PCMactuator assembly.

FIG. 10 is a diagram of an increase flow path, a decrease flow path, anda drain flow path within integrated PCM actuator assembly with radialgap transfer.

FIG. 11 is a side elevation view of an integrated PCM actuator assemblywith axial gap transfer.

FIG. 12 is a diagram of an increase flow path, a decrease flow path, anda drain flow path within integrated PCM actuator assembly with axial gaptransfer.

Although specific features of various embodiments may be shown in somedrawings and not in others, this is for convenience only. Any feature ofany drawing may be referenced and/or claimed in combination with anyfeature of any other drawing.

Unless otherwise indicated, the drawings provided herein are meant toillustrate features of embodiments of the disclosure. These features arebelieved to be applicable in a wide variety of systems comprising one ormore embodiments of the disclosure. As such, the drawings are not meantto include all conventional features known by those of ordinary skill inthe art to be required for the practice of the embodiments disclosedherein.

DETAILED DESCRIPTION

In the following specification and the claims, reference will be made toa number of terms, which shall be defined to have the followingmeanings.

The singular forms “a”, “an”, and “the” include plural references unlessthe context clearly dictates otherwise.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where the event occurs and instances where it does not.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about”, “approximately”, and “substantially”, are notto be limited to the precise value specified. In at least someinstances, the approximating language may correspond to the precision ofan instrument for measuring the value. Here and throughout thespecification and claims, range limitations may be combined and/orinterchanged, such ranges are identified and include all the sub-rangescontained therein unless context or language indicates otherwise.

The following detailed description illustrates embodiments of thedisclosure by way of example and not by way of limitation. It iscontemplated that the disclosure has general application to a method andsystem for supplying hydraulic fluid to an integrated PCM actuatorassembly.

Embodiments of the integrated PCM actuator assembly hydraulic fluidsupply system described herein provide hydraulic fluid to an integratedPCM actuator assembly of a gas turbine engine. The integrated PCMactuator assembly hydraulic fluid supply system includes a stationaryhydraulic fluid transfer sleeve circumscribing a hydraulic fluid portassembly which includes a plurality of hydraulic fluid ports. A fanblade pitch change actuator assembly is coupled in flow communicationwith the hydraulic fluid port assembly. The stationary hydraulic fluidtransfer sleeve is configured to deliver a flow of hydraulic fluid tothe hydraulic fluid port assembly which actuates the pitch actuatorassembly and controls the pitch of fan blades with the gas turbineengine.

The integrated PCM actuator assembly hydraulic fluid supply systemdescribed herein offers advantages over known methods of supplyinghydraulic fluid to an integrated PCM actuator assembly. Morespecifically, the integrated PCM actuator assembly described hereinsupplies hydraulic fluid directly to the actuator. Supplying hydraulicfluid directly to the actuator in the integrated PCM actuator assemblydecreases the weight of the actuator and the engine by eliminatingadditional mechanical parts. Furthermore, integrating the hydraulicfluid supply system into the actuator can improve reliability of theactuator.

FIG. 1 is a schematic cross-sectional view of a gas turbine engine inaccordance with an exemplary embodiment of the present disclosure. Inthe example embodiment, the gas turbine engine is a high-bypass turbofanjet engine 10, referred to herein as “turbofan engine 10.” As shown inFIG. 1, turbofan engine 10 defines an axial direction A (extendingparallel to a longitudinal centerline 12 provided for reference) and aradial direction R. In general, turbofan engine 10 includes a fansection 14 and a core turbine engine 16 disposed downstream from fansection 14.

The exemplary core turbine engine 16 depicted generally includes asubstantially tubular outer casing 18 that defines an annular inlet 20.Outer casing 18 encases, in serial flow relationship, a compressorsection including a booster or low pressure (LP) compressor 22 and ahigh pressure (HP) compressor 24; a combustion section 26; a turbinesection including a high pressure (HP) turbine 28 and a low pressure(LP) turbine 30; and a jet exhaust nozzle section 32. A high pressure(HP) shaft or spool 34 drivingly connects HP turbine 28 to HP compressor24. A low pressure (LP) shaft or spool 36 drivingly connects LP turbine30 to LP compressor 22. The compressor section, combustion section 26,turbine section, and nozzle section 32 together define a core airflowpath 37.

For the embodiment depicted, fan section 14 includes a variable pitchfan 38 having a plurality of fan blades 40 coupled to a disk 42 in aspaced apart manner. As depicted, fan blades 40 extend outwardly fromdisk 42 generally along radial direction R. Each fan blade 40 isrotatable relative to disk 42 about a pitch axis P by virtue of fanblades 40 being operatively coupled to a suitable pitch change mechanism44 configured to collectively vary the pitch of fan blades 40 in unison.Fan blades 40, disk 42, and pitch change mechanism 44 are togetherrotatable about longitudinal axis 12 by LP shaft 36 across a power gearbox 46. Power gear box 46 includes a plurality of gears for adjustingthe rotational speed of fan 38 relative to LP shaft 36 to a moreefficient rotational fan speed.

Referring still to the exemplary embodiment of FIG. 1, disk 42 iscovered by a rotatable front hub 48 aerodynamically contoured to promotean airflow through plurality of fan blades 40. Additionally, exemplaryfan section 14 includes an annular fan casing or outer nacelle 50 thatcircumferentially surrounds fan 38 and/or at least a portion of coreturbine engine 16. It should be appreciated that nacelle 50 may beconfigured to be supported relative to core turbine engine 16 by aplurality of circumferentially-spaced outlet guide vanes 52. Moreover, adownstream section 54 of nacelle 50 may extend over an outer portion ofcore turbine engine 16 so as to define a bypass airflow passage 56therebetween.

During operation of turbofan engine 10, a volume of air 58 entersturbofan engine 10 through an associated inlet 60 of nacelle 50 and/orfan section 14. As volume of air 58 passes across fan blades 40, a firstportion of air 58 as indicated by arrows 62 is directed or routed intobypass airflow passage 56 and a second portion of air 58 as indicated byarrow 64 is directed or routed into core air flowpath 37, or morespecifically into LP compressor 22. The ratio between first portion ofair 62 and second portion of air 64 is commonly known as a bypass ratio.The pressure of second portion of air 64 is then increased as it isrouted through high pressure (HP) compressor 24 and into combustionsection 26, where it is mixed with fuel and burned to provide combustiongases 66.

Combustion gases 66 are routed through HP turbine 28 where a portion ofthermal and/or kinetic energy from combustion gases 66 is extracted viasequential stages of HP turbine stator vanes 68 that are coupled toouter casing 18 and HP turbine rotor blades 70 that are coupled to HPshaft or spool 34, thus causing HP shaft or spool 34 to rotate, therebysupporting operation of HP compressor 24. Combustion gases 66 are thenrouted through LP turbine 30 where a second portion of thermal andkinetic energy is extracted from combustion gases 66 via sequentialstages of LP turbine stator vanes 72 that are coupled to outer casing 18and LP turbine rotor blades 74 that are coupled to LP shaft or spool 36,thus causing LP shaft or spool 36 to rotate, thereby supportingoperation of LP compressor 22 and/or rotation of fan 38.

Combustion gases 66 are subsequently routed through jet exhaust nozzlesection 32 of core turbine engine 16 to provide propulsive thrust.Simultaneously, the pressure of first portion of air 62 is substantiallyincreased as first portion of air 62 is routed through bypass airflowpassage 56 before it is exhausted from a fan nozzle exhaust section 76of turbofan engine 10, also providing propulsive thrust. HP turbine 28,LP turbine 30, and jet exhaust nozzle section 32 at least partiallydefine a hot gas path 78 for routing combustion gases 66 through coreturbine engine 16.

It should be appreciated, however, that exemplary turbofan engine 10depicted in FIG. 1 is by way of example only, and that in otherexemplary embodiments, turbofan engine 10 may have any other suitableconfiguration. It should also be appreciated, that in still otherexemplary embodiments, aspects of the present disclosure may beincorporated into any other suitable gas turbine engine. For example, inother exemplary embodiments, aspects of the present disclosure may beincorporated into, e.g., a turboprop engine and unducted fan engine.

FIG. 2 is a side elevation view of a fan rotor assembly 200 including anintegrated PCM actuator assembly 202 in accordance with an exemplaryembodiment of the present disclosure. Fan rotor assembly 200 includesintegrated PCM actuator assembly 202, an epicyclic gearbox 204, a powerengine rotor 206, a stationary hydraulic fluid transfer sleeve 208, anda hub assembly 210. Hub assembly 210 includes a unison ring 212, aplurality of fan blade trunnion yokes 214, a plurality of trunnionassemblies 216, and a plurality of fan blades 218. In some embodiments,LP shaft 36 (shown in FIG. 1) is fixedly coupled to epicyclic gearbox204 which is rotationally coupled to power engine rotor 206. Powerengine rotor 206 is rotationally coupled to hub assembly 210 andintegrated PCM actuator assembly 202 which is rotationally coupled tounison ring 212 through integrated PCM actuator assembly 202. Hubassembly 210 is rotationally coupled to fan blades 218. Unison rings 212are rotationally coupled to fan blade trunnion yokes 214 which arerotationally coupled to trunnion assemblies 216. Trunnion assemblies 216are rotationally coupled to fan blades 218. Stationary hydraulic fluidtransfer sleeve 208 is coupled to supports (not shown) within epicyclicgearbox 204 and circumscribes integrated PCM actuator assembly 202.Stationary hydraulic fluid transfer sleeve 208 is coupled in flowcommunication with integrated PCM actuator assembly 202.

In operation, LP shaft 36 (shown in FIG. 1) is configured to rotate aplurality of gears (not shown) within epicyclic gearbox 204 which areconfigured to rotate power engine rotor 206. Power engine rotor 206 isconfigured to rotate integrated PCM actuator assembly 202 which isconfigured to rotate unison rings 212. Unison ring 212 is configured torotate fan blade trunnion yokes 214 which are configured to rotatetrunnion assemblies 216. Trunnion assemblies 216 are configured torotate fan blades 218 about their respective axis. Stationary hydraulicfluid transfer sleeve 208 is configured to remain stationary whileintegrated PCM actuator assembly 202 is configured to rotate along withthe fan module.

Stationary hydraulic fluid transfer sleeve 208 is coupled in flowcommunication with integrated PCM actuator assembly 202. Hydraulic fluidpressure from stationary hydraulic fluid transfer sleeve 208 actuatesintegrated PCM actuator assembly 202 which rotates unison ring 212 abouta radially extending pitch axis of rotation 220. Unison ring 212translates fan blade trunnion yokes 214 along an arcuate path, whichrotate respective trunnion assemblies 216 about radially extending pitchaxis of rotation 220. Trunnion assemblies 216 are configured to rotatefan blades 218 about radially extending pitch axis of rotation 220.

FIG. 3 is an exploded view of an integrated PCM actuator assembly 300 inaccordance with an exemplary embodiment of the present disclosure.Integrated PCM actuator assembly 300 receives hydraulic fluid through aradial gap transfer. Integrated PCM actuator assembly 300 includes anactuator shell 302, a hydraulic fluid transfer sleeve 304, a pitchactuator 306, and an end cap 308. Actuator shell 302 includes ahydraulic fluid port assembly 310 extending aft in axial direction Afrom actuator shell 302. Hydraulic fluid transfer sleeve 304circumscribes hydraulic fluid port assembly 310. Actuator shell 302partially circumscribes pitch actuator 306 which includes a pitchactuator shaft 312 extending forward in axial direction A from pitchactuator 306 through end cap 308 to unison rings 212 (shown in FIG. 2).End cap 308 is coupled to the axially forward end of actuator shell 302.

FIG. 4 is two perspective views of a pitch actuator 400. FIG. 4a is aperspective view of pitch actuator 400. FIG. 4b is a cutaway perspectiveview of pitch actuator 400. Pitch actuator 400 includes a plurality ofpitch actuator vanes 404 extending radially outward from pitch actuatorshaft 402 and a mechanical transfer range limiter 406 extending aft inaxial direction A from pitch actuator 400. Pitch actuator 400 alsoincludes a pitch actuator void 408 extending through pitch actuatorshaft 402.

FIG. 5 is two perspective views of an actuator shell 502, a hydraulicfluid transfer sleeve 504, and an end cap 506. FIG. 5a is a perspectiveview of actuator shell 502, hydraulic fluid transfer sleeve 504, and endcap 506. FIG. 5b is a cutaway perspective view of actuator shell 502,hydraulic fluid transfer sleeve 504, and end cap 506. Actuator shell 502includes an actuator cap 508 coupled to the axially aft end of actuatorshell 502. Hydraulic fluid port assembly 510 extends aft in axialdirection A from actuator cap 508 and is circumscribed by hydraulicfluid transfer sleeve 504. Actuator shell 502 also includes a pluralityof actuator shell vanes 512 extending radially inward from actuatorshell 502.

FIG. 6 is an axial view of the integrated PCM actuator assembly 300shown in FIGS. 3, 4, 5, and 7 along lines 6-6 in FIGS. 4, 5, and 7. FIG.6a is an axial view of the integrated PCM actuator assembly 300 in anon-mechanically limited position. FIG. 6b is an axial view of theintegrated PCM actuator 300 in a mechanically limited position. FIG. 6introduces the structure of integrated PCM actuator assembly 300 withpitch actuator 400 disposed within actuator shell 502. FIG. 6 will alsobe discussed with the operational embodiments of integrated PCM actuatorassembly 300.

Pitch actuator vanes 404 extend radially outward from pitch actuator 400to an inner radial surface 514 of actuator shell 502. Actuator shellvanes 512 extend radially inward from actuator shell 502 to an outerradial surface 410 of pitch actuator 400. Each actuator shell vane 512extends between two pitch actuator vanes 404 forming an alternatingcircumferential pattern of actuator shell vanes 512 and pitch actuatorvanes 404. A decrease cavity 602 and an increase cavity 604 are formedfrom the volume between actuator shell vanes 512 and pitch actuatorvanes 404. Each actuator shell vane 512 is adjacent to decrease cavity602 on one side and increase cavity 604 on the other side.

FIG. 7 is a side elevation view of an integrated PCM actuator assembly300 in accordance with an exemplary embodiment of the presentdisclosure. FIG. 8 is an overlay of the internal flow passages ofactuator shell 502 on pitch actuator 400. FIG. 9 is an axial view of theintegrated PCM actuator assembly shown in FIGS. 3, 4, 5, and 8 alonglines 10-10 in FIGS. 4, 5, and 8. FIG. 9a depicts a normal operationalembodiment of integrated PCM actuator assembly 300. FIG. 9b depicts adecreased pitch operational embodiment of integrated PCM actuatorassembly 300. FIG. 10 is a diagram of an increase flow path 610, adecrease flow path 630, and a drain flow path 650 within integrated PCMactuator assembly 300. Increase flow path 610, decrease flow path 630,and drain flow path 650 are described below with reference to FIGS.7-10. The internal flow passages are shown with increased clarity inFIG. 8 with removal of the outer casing. The ports that feed theinternal passages are best depicted in FIG. 6, which has previously beendiscussed. FIG. 9 demonstrates that the supply lines are oriented tocreate fail safes. Finally, FIG. 10 presents a high level schematic ofincrease flow path 610, decrease flow path 630, and drain flow path 650.A hydraulic fluid supply system 516 supplies hydraulic fluid to all flowpaths.

Increase flow path 610 includes a stationary increase delivery tube 612coupled in flow communication with hydraulic fluid supply system 516 andhydraulic fluid transfer sleeve 504. A rotating increase deliverychannel 614 is disposed within hydraulic fluid port assembly 510 andreceives hydraulic fluid from stationary increase delivery tube 612.Rotating increase delivery channel 614 directs hydraulic fluid to anincrease actuator passage 616 disposed within hydraulic fluid portassembly 510 and actuator cap 508. Increase actuator passage 616 iscoupled in flow communication with an increase actuator cap deliverychannel 618. Increase actuator cap delivery channel 618 channelshydraulic fluid circumferentially around actuator cap 508 and is coupledin flow communication with a plurality of increase actuator vanepassages 620 which extend forward in axial direction A through actuatorvanes 512. Increase actuator vane passages 620 channels hydraulic fluidto a plurality of increase delivery tubes 622 which deliver hydraulicfluid to increase cavities 604. Hydraulic fluid delivered to increasecavities 604 increases the hydraulic fluid pressure in increase cavities604. Increased hydraulic fluid pressure in increase cavities 604increases the hydraulic fluid pressure on one side of pitch actuatorvanes 404 which rotates pitch actuator 400 and rotate unison ring 212.

Decrease flow path 630 includes a stationary decrease delivery tube 632coupled in flow communication with hydraulic fluid supply system 516 andhydraulic fluid transfer sleeve 504. A rotating decrease deliverychannel 634 is disposed within hydraulic fluid port assembly 510 andreceives hydraulic fluid from stationary decrease delivery tube 632.Rotating decrease delivery channel 634 directs hydraulic fluid to adecrease actuator passage 636 disposed within hydraulic fluid portassembly 510 and actuator cap 508. Decrease actuator passage 636 iscoupled in flow communication with mechanical transfer range limiter406. Mechanical transfer range limiter 406 channels hydraulic fluid to adecrease range limiter channel 638 which channels hydraulic fluid to adecrease actuator cap delivery channel 640. Decrease actuator capdelivery channel 640 channels hydraulic fluid circumferentially aroundactuator cap 508 and is coupled in flow communication with a pluralityof decrease actuator vane passages 642 which extend forward in axialdirection A through actuator vanes 512. Decrease actuator vane passages642 channels hydraulic fluid to a plurality of decrease delivery tubes644 which deliver hydraulic fluid to decrease cavities 602.

The flow of hydraulic fluid in drain flow path 650 is bidirectional.Drain flow path 650 can deliver hydraulic fluid to decrease cavities 602from hydraulic fluid supply system 516 or can deliver hydraulic fluid tohydraulic fluid supply system 516 from decrease cavities 602. Duringnormal operations drain flow path 650 is not pressurized with hydraulicfluid. Drain flow path 650 includes a stationary drain delivery tube 652coupled in flow communication with hydraulic fluid supply system 516 andhydraulic fluid transfer sleeve 504. A rotating drain delivery channel654 is disposed within hydraulic fluid port assembly 510 and receiveshydraulic fluid from stationary drain delivery tube 652. Rotating draindelivery channel 654 directs hydraulic fluid to a decrease actuatorpassage 656 disposed within hydraulic fluid port assembly 510 andactuator cap 508. Drain actuator passage 656 is coupled in flowcommunication with mechanical transfer range limiter 406. Mechanicaltransfer range limiter 406 channels hydraulic fluid to a drain rangelimiter channel 658 which channels hydraulic fluid to a drain actuatorcap delivery channel 660. Drain actuator cap delivery channel 660channels hydraulic fluid circumferentially around actuator cap 508 andis coupled in flow communication with a plurality of drain actuator vanepassages 662 which extend forward in axial direction A through actuatorvanes 512. Drain actuator vane passages 662 channels hydraulic fluid toa plurality of drain delivery tubes 664 which deliver hydraulic fluid todecrease cavities 602.

FIG. 6a depicts a normal operational embodiment of integrated PCMactuator assembly 300. The hydraulic fluid pressure on both sides ofpitch actuator vanes 404 are equal and the volumes of increase cavity604 and decrease cavity 602 are also equal. Pitch actuator 400 is notrotated and unison rings 212 are not rotated. FIG. 6b depicts adecreased pitch operational embodiment of integrated PCM actuatorassembly 300. The hydraulic fluid pressure in decrease cavity 602 isincreased by the introduction of hydraulic fluid to decrease flow path630. Increased hydraulic fluid pressure in decrease cavities 602increases the hydraulic fluid pressure on one side of pitch actuatorvanes 404 which rotates pitch actuator 400 and rotate unison ring 212.

FIG. 9a depicts a normal operational embodiment of integrated PCMactuator assembly 300. Mechanical transfer range limiter 406 is in flowcommunication with decrease actuator passage 636 and decrease rangelimiter channel 638. Hydraulic fluid is channeled through decrease flowpassage 630 as previously discussed. As pitch actuator 400 rotatesfurther from normal operating position, mechanical transfer rangelimiter 406 rotates away from flow communication from decrease actuatorpassage 636 and into flow communication with drain actuator passage 656.FIG. 9b depicts a decreased pitch operational embodiment of integratedPCM actuator assembly 300. During normal operations, drain flow path 650is not pressurized. When mechanical transfer range limiter 406 rotatesinto flow communication with drain actuator passage 656 and drain rangelimiter channel 658, pressurized hydraulic fluid drains from decreasecavity 602 into drain flow path 650 as previously discussed. Hydraulicfluid drains from decrease cavity 602 to hydraulic fluid supply system516. Draining hydraulic fluid from decrease cavity 602 decreases thehydraulic fluid pressure in decrease cavity 602 which halts the rotationof pitch actuator 400 in the decrease direction. As pitch actuator 400rotates further in the opposite direction, mechanical transfer rangelimiter 406 rotates away from flow communication from drain actuatorpassage 656 and into flow communication with decrease actuator passage636, allowing once again for rotation in both directions.

FIG. 11 is a side elevation view of an integrated PCM actuator assembly700 in accordance with an exemplary embodiment of the radial gaptransfer of the present disclosure. Integrated PCM actuator assemblies300 and 700 are the same item except integrated PCM actuator assembly300 receives hydraulic fluid through an axial gap transfer whileintegrated PCM actuator assembly 700 receives hydraulic fluid through aradial gap transfer. For clarity, the structural components ofintegrated PCM actuator assembly 700 are labeled with 700 series numberswhile fluid channels and passages within integrated PCM actuatorassembly 700 are labeled with 800, 900, and 1000 series numbers (shownwith more clarity in FIG. 12). Integrated PCM actuator assembly 700includes an actuator shell 702, a hydraulic fluid transfer assembly 704,a pitch actuator 706, and an end cap 708. Hydraulic fluid transferassembly 704 extends aft in axial direction A from actuator shell 702.Actuator shell 702 partially circumscribes pitch actuator 706 whichincludes a pitch actuator shaft 712 extending forward in axial directionA from pitch actuator 706 through end cap 708 to unison rings 212 (shownin FIG. 2). End cap 708 is coupled to the axially forward end ofactuator shell 702.

Pitch actuator 706 includes a plurality of pitch actuator vanes 714extending radially outward from pitch actuator shaft 712 and amechanical transfer range limiter 716 extending aft in axial direction Afrom pitch actuator 706. Actuator shell 702 includes an actuator cap 720coupled to the axially aft end of actuator shell 702. Actuator shellalso includes a plurality of actuator shell vanes 722 extending radiallyinward from actuator shell 702. Pitch actuator vanes 714 extend radiallyoutward from pitch actuator 706 to an inner radial surface 724 ofactuator shell 706. Actuator shell vanes 722 extend radially inward fromactuator shell 706 to an outer radial surface 726 of pitch actuator 706.Each actuator shell vane 722 extends between two pitch actuator vanes714 forming an alternating circumferential pattern of actuator shellvanes 722 and pitch actuator vanes 714. A decrease cavity (not shown)and an increase cavity (not shown) are formed from the volume betweenactuator shell vanes 722 and pitch actuator vanes 714. Each actuatorshell vane 722 is adjacent to decrease cavity on one side and increasecavity on the other side.

FIG. 12 is a diagram of an increase flow path 800, a decrease flow path900, and a drain flow path 1000 within integrated PCM actuator assembly700. A hydraulic fluid supply system 732 supplies hydraulic fluid to allflow paths. Increase flow path 800 includes a stationary increasedelivery tube 802 coupled in flow communication with hydraulic fluidsupply system 732 and hydraulic fluid transfer assembly 704. Stationaryincrease delivery tube 802 delivers hydraulic fluid to a hydraulic fluidtransfer assembly increase passage 804 disposed within hydraulic fluidtransfer assembly 704. A rotating increase delivery channel 806 isdisposed within actuator cap 720 and receives hydraulic fluid fromhydraulic fluid transfer assembly passage 804. Rotating increasedelivery channel 806 directs hydraulic fluid to an increase actuator capdelivery channel 808. Increase actuator cap delivery channel 808channels hydraulic fluid circumferentially around actuator cap 720 andis coupled in flow communication with a plurality of increase actuatorvane passages 810 which extend forward in axial direction A throughactuator vanes 722. Increase actuator vane passages 810 channelshydraulic fluid to a plurality of increase delivery tubes 812 whichdeliver hydraulic fluid to increase cavities.

Hydraulic fluid delivered to increase cavities increases the hydraulicfluid pressure in increase cavities (refer to FIGS. 6 and 9 as thisregion of integrated PCM actuator assembly 700 is the same as integratedPCM actuator assembly 300). Increased hydraulic fluid pressure inincrease cavities increases the hydraulic fluid pressure on one side ofpitch actuator vanes 714 which rotates pitch actuator 706 and rotateunison ring 212 (shown in FIG. 2).

Decrease flow path 900 includes a stationary decrease delivery tube 902coupled in flow communication with hydraulic fluid supply system 732 andhydraulic fluid transfer assembly 704. Stationary decrease delivery tube902 delivers hydraulic fluid to a hydraulic fluid transfer assemblydecrease passage 904 disposed within hydraulic fluid transfer assembly704. A rotating decrease delivery channel 906 is disposed withinactuator cap 720 and receives hydraulic fluid from hydraulic fluidtransfer assembly decrease passage 904. Rotating decrease deliverychannel 906 directs hydraulic fluid to mechanical transfer range limiter716 which directs hydraulic fluid to a decrease range limiter channel908. Decrease range limiter channel 908 channels hydraulic fluid todecrease actuator cap delivery channel 910 which channels hydraulicfluid circumferentially around actuator cap 720 and is coupled in flowcommunication with a plurality of decrease actuator vane passages 912which extend forward in axial direction A through actuator vanes 722.Decrease actuator vane passages 912 channels hydraulic fluid to aplurality of decrease delivery tubes 914 which deliver hydraulic fluidto decrease cavities.

The flow of hydraulic fluid in drain flow path 1000 is bidirectional.Drain flow path 1000 can deliver hydraulic fluid to decrease cavitiesfrom hydraulic fluid supply system 516 or can deliver hydraulic fluid tohydraulic fluid supply system 516 from decrease cavities. During normaloperations drain flow path 1000 is not pressurized with hydraulic fluid.Drain flow path 1000 includes a stationary drain delivery tube 1002coupled in flow communication with hydraulic fluid supply system 732 andhydraulic fluid transfer assembly 704. Stationary drain delivery tube1002 delivers hydraulic fluid to a hydraulic fluid transfer assemblydrain passage 1004 disposed within hydraulic fluid transfer assembly704. A rotating drain delivery channel 1006 is disposed within actuatorcap 720 and receives hydraulic fluid from hydraulic fluid transferassembly drain passage 1004. Rotating drain delivery channel 1006directs hydraulic fluid to mechanical transfer range limiter 716 whichdirects hydraulic fluid to a drain range limiter channel 1008. Drainrange limiter channel 1008 channels hydraulic fluid to drain actuatorcap delivery channel 1010 which channels hydraulic fluidcircumferentially around actuator cap 720 and is coupled in flowcommunication with a plurality of drain actuator vane passages 1012which extend forward in axial direction A through actuator vanes 722.Drain actuator vane passages 1012 channels hydraulic fluid to aplurality of drain delivery tubes 1014 which deliver hydraulic fluid todecrease cavities.

During normal operations, the hydraulic fluid pressure on both sides ofpitch actuator vanes 714 are equal and the volumes of increase cavityand decrease cavity are also equal. Pitch actuator 706 is not rotatedand unison rings 212 are not rotated. During decreased pitch operations,the hydraulic fluid pressure in decrease cavity is increased by theintroduction of hydraulic fluid to decrease flow path 900. Increasedhydraulic fluid pressure in decrease cavities increases the hydraulicfluid pressure on one side of pitch actuator vanes 714 which rotatespitch actuator 706 and rotate unison ring 212. Mechanical transfer rangelimiter 716 operates in the same manner as mechanical transfer limiter316 and prevents pitch actuator 706 from rotating too far.

The above-described hydraulic fluid supply systems provide an efficientmethod for supplying hydraulic fluid to an integrated PCM actuatorassembly. Specifically, the above-described hydraulic fluid supplysystem delivers hydraulic fluid directly to the actuator. When hydraulicfluid is delivered directly to the actuator, less equipment is needed todeliver hydraulic fluid. As such, providing hydraulic fluid directly tothe actuator improves the reliability of the integrated PCM actuatorassembly. Additionally, integrating the hydraulic fluid supply systemwithin the integrated PCM actuator assembly reduces the weight of theengine.

Exemplary embodiments of hydraulic fluid supply systems are describedabove in detail. The hydraulic fluid supply systems, and methods ofoperating such systems and devices are not limited to the specificembodiments described herein, but rather, components of systems and/orsteps of the methods may be utilized independently and separately fromother components and/or steps described herein. For example, the methodsmay also be used in combination with other systems requiring hydraulicfluid, and are not limited to practice with only the systems and methodsas described herein. Rather, the exemplary embodiment can be implementedand utilized in connection with many other machinery applications thatare currently configured to receive and accept hydraulic fluid supplysystems.

Example methods and apparatus for supplying hydraulic fluid to anintegrated PCM actuator assembly are described above in detail. Theapparatus illustrated is not limited to the specific embodimentsdescribed herein, but rather, components of each may be utilizedindependently and separately from other components described herein.Each system component can also be used in combination with other systemcomponents.

This written description uses examples to describe the disclosure,including the best mode, and also to enable any person skilled in theart to practice the disclosure, including making and using any devicesor systems and performing any incorporated methods. The patentable scopeof the disclosure is defined by the claims, and may include otherexamples that occur to those skilled in the art. Such other examples areintended to be within the scope of the claims if they have structuralelements that do not differ from the literal language of the claims, orif they include equivalent structural elements with insubstantialdifferences from the literal languages of the claims.

What is claimed is:
 1. A variable pitch propeller assembly comprising: ahub rotatable about a shaft having an axis of rotation; a plurality ofpropeller blade assemblies spaced circumferentially about said hub, eachpropeller blade assembly of the plurality of propeller blade assembliesconfigured to rotate a respective propeller blade about a radiallyextending pitch axis of rotation; a hydraulic fluid port assemblyintegrally formed and rotatable with the shaft, the hydraulic fluid portassembly comprising at least three hydraulic fluid ports configured toreceive respective flows of hydraulic fluid from a stationary hydraulicfluid transfer sleeve at least partially surrounding said port assembly;and a pitch actuator assembly coupled in flow communication with the atleast three hydraulic fluid ports through respective hydraulic fluidtransfer tubes extending from said hydraulic fluid port assembly to saidpitch actuator assembly.
 2. The assembly of claim 1, wherein said atleast three hydraulic transfer tubes comprise an increase transfer tube,a decrease transfer tube, and a drain.
 3. The assembly of claim 1,wherein said pitch actuator assembly comprises a linear actuation memberconfigured to translate an axial movement driven by at least one of saidhydraulic fluid transfer tubes into a rotation about the pitch axis ofrotation.
 4. The assembly of claim 1, wherein said pitch actuatorassembly comprises a rotary actuation member configured to translate acircumferential movement driven by at least one of said hydraulic fluidtransfer tubes into a rotation about the pitch axis of rotation.
 5. Theassembly of claim 1, wherein said hydraulic fluid port assembly isconfigured to receive respective flows of hydraulic fluid from astationary hydraulic fluid transfer sleeve in a radial direction.
 6. Theassembly of claim 1, wherein said hydraulic fluid port assembly isconfigured to receive respective flows of hydraulic fluid from astationary hydraulic fluid transfer sleeve in an axial direction.
 7. Theassembly of claim 1, wherein said pitch actuator assembly is coupled tothe plurality of propeller blade assemblies to selectively control apitch of the propeller blades.
 8. The assembly of claim 7, wherein saidpitch actuator assembly comprises a travel stop configured to limit arotation of at least one of said pitch actuator assembly and saidplurality of propeller blade assemblies.
 9. The assembly of claim 8,wherein said travel stop comprises a mechanical hydraulic fluid cutoffdevice configured to cutoff flow to said pitch actuator assembly throughsaid hydraulic fluid transfer tubes.
 10. The assembly of claim 8,wherein said travel stop comprises a mechanical travel limit deviceconfigured to prevent movement of said pitch actuator assembly outside apredetermined range.
 11. A variable pitch turbofan gas turbine enginecomprising: a core engine including a multistage compressor; and a fanassembly comprising an axis of rotation and powered by said core engine,said fan assembly comprising: a hub rotatable about a shaft having anaxis of rotation; a plurality of propeller blade assemblies spacedcircumferentially about said hub, each propeller blade assembly of theplurality of propeller blade assemblies configured to rotate arespective propeller blade about a radially extending pitch axis ofrotation; a hydraulic fluid port assembly integrally formed androtatable with the shaft, the hydraulic fluid port assembly comprisingat least three hydraulic fluid ports configured to receive respectiveflows of hydraulic fluid from a stationary hydraulic fluid transfersleeve at least partially surrounding said port assembly; and a pitchactuator assembly coupled in flow communication with the at least threehydraulic fluid ports through respective hydraulic fluid transfer tubesextending axially from said hydraulic fluid port assembly to said pitchactuator assembly, said pitch actuator assembly coupled to the pluralityof propeller blade assemblies to selectively control a pitch of thepropeller blades.
 12. The variable pitch turbofan gas turbine engine ofclaim 11, wherein said at least three hydraulic transfer tubes comprisean increase transfer tube, a decrease transfer tube, and a drain. 13.The variable pitch turbofan gas turbine engine of claim 11, wherein saidpitch actuator assembly comprises a linear actuation member configuredto translate an axial movement driven by at least one of said hydraulicfluid transfer tubes into a rotation about the pitch axis of rotation.14. The variable pitch turbofan gas turbine engine of claim 11, whereinsaid pitch actuator assembly comprises a rotary actuation memberconfigured to translate a circumferential movement driven by at leastone of said hydraulic fluid transfer tubes into a rotation about thepitch axis of rotation.
 15. The variable pitch turbofan gas turbineengine of claim 11, wherein said hydraulic fluid port assembly isconfigured to receive respective flows of hydraulic fluid from astationary hydraulic fluid transfer sleeve in a radial direction. 16.The variable pitch turbofan gas turbine engine of claim 11, wherein saidhydraulic fluid port assembly is configured to receive respective flowsof hydraulic fluid from a stationary hydraulic fluid transfer sleeve inan axial direction.
 17. The variable pitch turbofan gas turbine engineof claim 11, wherein said pitch actuator assembly is coupled to theplurality of propeller blade assemblies to selectively control a pitchof the propeller blades.
 18. The variable pitch turbofan gas turbineengine of claim 17, wherein said pitch actuator assembly comprises atravel stop configured to limit a rotation of at least one of said pitchactuator assembly and said plurality of propeller blade assemblies. 19.The variable pitch turbofan gas turbine engine of claim 18, wherein saidtravel stop comprises a mechanical hydraulic fluid cutoff deviceconfigured to cutoff flow to said pitch actuator assembly through saidhydraulic fluid transfer tubes.
 20. The variable pitch turbofan gasturbine engine of claim 18, wherein said travel stop comprises amechanical travel limit device configured to prevent movement of saidpitch actuator assembly outside a predetermined range.